1. Field of the Invention
The present invention relates to an apparatus and method for generating coefficient data, an apparatus and method for processing an information signal using the same, an apparatus and method for obtaining coefficient data used therefor, and an information providing medium. More specifically, the present invention relates to a coefficient data generating apparatus, etc. in which coefficient data that is used when converting a first information signal into a second information signal is generated by generating elements of a summation matrix in accordance with the value of a predetermined parameter by a generating equation and using the summation matrix composed of the elements, so that the second information signal in accordance with the value of the predetermined parameter can be favorably obtained from the first information signal without incurring the need for a larger memory for storing coefficient data.
2. Description of the Related Art
Hitherto, conversion of signal format, for example, from an SD (Standard Definition) signal called 525i signal into an HD (High Definition) signal called 1050i signal, has been proposed. 525i signal refers to an interlaced image signal with a line count of 525, and 1050i signal refers to an interlaced image signal with a line count of 1,050.
FIG. 12 shows the relationship between pixel positions of a 525i signal and a 1050i signal, in which larger dots represent pixels of 525i signal and smaller dots represent pixels of 1050i signal. The positions of pixels in odd-numbered fields are shown in solid lines and the positions of pixels in even-numbered fields are shown in broken lines. When a 525i signal is converted into a 1050i signal, four pixels of 1050i signal must be obtained in association with one pixel of 525i signal in each of odd-numbered and even-numbered fields.
It has hitherto been proposed that, when obtaining pixel data of 1050i signal from pixel data of 525i signal in order to execute a format conversion as above, coefficient data for an estimate equation in accordance with phase of each of the pixels of 1050i signal corresponding to the pixel of 525i signal be stored in a memory so that pixel data of 1050i signal will be obtained by the estimate equation using the coefficient data.
In the technique of obtaining pixel data of 1050i signal by the estimate equation as described above, the resolution of an image based on the 1050i signal is fixed, not allowing the resolution to be changed as desired in accordance with the content of the image, etc. as has been the case for adjustment of contrast, sharpness, etc. It is possible to prepare coefficient data associated with a plurality of resolutions so that the user is allowed to adjust the resolution as desired; however, this incurs increased amount of memory being required to store the coefficient data, leading to increased cost of the apparatus.